Suturing tissue or organs is a tedious and delicate procedure. This is due principally to the use of one single strand of suture thread, the thinness of the suturing thread, as well as its tendency to twist about its length. In one type of suturing procedure, the thread is directed through a tissue and the free ends thereof are wrapped to define a half-hitch knot that froths a closed loop, the diameter of which can be reduced ultimately to the point that the thread is cinched at the tissue. As twisting of the thread occurs, restriction of the loop is inhibited, possibly to the point that it is impossible to cinch the knot at the body tissue, as required. Even after one half-hitch knot is formed and properly cinched, the twisting problem persists and may interfere with, or prevent, the subsequent formation of additional half-hitch knots as would “lock” the suture. When this occurs, the surgeon may be required to cut the suture and re-start the process. This process is time consuming. These problems increase the overall time of the operation and contribute undesirably to hand, and overall, surgeon fatigue.
Most suture knots are tied completely by hand or, in instances where the fingers cannot reach, using surgical instruments. Certain apparatuses have been proposed which assist in forming suture knots. However, the prior apparatuses and associated methods of use provide assistance only in tying relatively simple knots or only small portions of more complicated knots.
Other common knots used for sutures are the square and the surgeon's knots. The square knot is a simple knot, but difficult to fashion solely with surgical instruments such as are necessary in endoscopic surgical procedures. However, once formed, the square knot may easily become untied.
Impetus for developing improved knots along with practical methods and apparatuses for their formation arises from the advancements and greater utilization of endoscopic procedures. Endoscopic and interventional procedures are currently hampered by the inability to easily tie knots within the body and other relatively inaccessible involved spaces. FIG. 1 illustrates a single strand of suture used to seal a blood vessel puncture site. As described above, suture knots are formed utilizing one single strand of suture thread 102. One method to tie a knot is by inserting a needle into a hollow body cavity, passing the needle through the tissue or blood vessel wall 104, bringing the needle out to the exterior, creating a tissue cinching loop 106 by manually developing a knot 108 and then locking the tissue cinching loop 106 into position by pulling on the end of the suture 101.
Currently, to release the tissue cinching loop 106 within the patient, the skin of the patient is depressed and the thread 102 is cut at some level below the skin. The acts of depressing and cutting are extra steps that a surgeon must perform. Furthermore, having the thread near the skin may increase the chance of infection to the patient. Additionally, the tissue cinching loop 106 may not adequately close the puncture site 110 causing blood to flow out of the blood vessel. Moreover, the entire suture thread 102 directly contacts the tissue or blood vessel wall 104 which may cause lacerations and tearing of the tissue 104 resulting in additional injury and requiring additional repair to the blood vessel puncture site 110.
Another method to perform the suturing in the interior of the body, is with the use of a curved needle with a fine suturing thread. It is held with a gun-shaped needle holder or grasper. The needle holder includes a clamp to securely hold the needle. The clamp can be rotated through 360° for maneuvering the needle to perform the desired stitching. The drawbacks of endoscopic and similar surgery are both the distance the suturing site is located inside the body as well as the limited space available within the body since manipulation of the surgical instruments themselves are used for the suturing process. With respect to the latter, a problem arises in manipulating the curved needle to easily tie a knot to close the surgical incision in situ. Many manipulations of the needle, needle holder, and suture thread are required for each suturing knot that is placed at the incision site.
Suture knots may also be used with other apparatuses such as an anchor and pulley system, suture pusher, and the like. However, significant limitations relating to current apparatuses and methods for the formation of suture knots include: (1) being limited to the formation of simple knots such as the square knot; (2) involving knots which require the manipulation of both ends of a length of suture filament which, accordingly, cannot be substantially tied prior to surgery or merely slipped into place; (3) requiring multiple manipulations outside of the surgical incision with loops thereby formed being afterwards coaxed toward the suture site; and (4) requiring the depression of the skin surface and cutting of excess suture from the body.
Extra-corporeal suturing, knots being tied outside the body to thereafter be slipped into position, has also been used in the past. It requires directing a suture carrying needle through a cannula, through internal body tissue, and out the proximal end of the cannula so that the free ends of the suturing thread are accessible from externally of the cavity. The surgeon then manipulates the free ends of the suturing thread by wrapping the threads in such a manner as to define a cinching loop in the form of a half-hitch knot. An elongate “pusher” rod, with a bifurcated free end, is engaged with one of the free ends of the thread in the vicinity of where they are wrapped and pressed through the cannula, while at the same time holding both free thread ends projecting away from the loop. As this takes place, the cinching loop diameter restricts to the point that it is ultimately cinched at the tissue.
This procedure is convenient from the standpoint that the half-hitch knots can be formed from externally of the body cavity. However, this introduces other complications. The problem of thread tangling persists. Further, the procedure is inherently awkward by requiring that the free ends of the suture projecting away from the loop be held taut as a pusher is pressed through the cannula to reduce the loop diameter. Thus, there are three manipulation points—the two free ends of the thread projecting away from the loop must be held and one of the threads at the wrapped portion of the loop must be pressed through the cannula. The result is that the procedure may require two sets of hands.
Further, the thread is prone to escaping from the open free end of the pusher. When this occurs, the surgeon is required to attempt to reposition the thread in the pusher end. This is a difficult and time consuming procedure that may be made impossible by twisting of the thread that occurs within the cavity. The end result of this may be that the surgeon may be required to remove the partially locked suture and re-start the procedure.
Additionally, since the thread is prone to twisting, the thread may bind as the loop diameter is restricted. Excessive pressure exerted by the pusher on the thread with this condition may result in thread breakage and/or damage to the tissue.
Sutures may be used for many reasons, including the formation of cinching loops. One reason for the use of a cinching loop is to limit blood flow, in tourniquet-fashion, from blood vessels termed “bleeders” or to close arterial punctures. Another may be to join two organs or the like together. Another may be to secure an object at a certain position. Whatever the reason for the use of a cinching loop, there exists a need for an more efficient, less complicated, safer, and simple way to form and release the cinching loop within the body.